An exemplary reinforcement assembly includes, among other things, a heel kick that extends horizontally between rockers of an electrified vehicle, and a reinforcement bracket that horizontally overlaps with the heel kick and is secured to an outboard portion of the heel kick. An exemplary reinforcement method includes, among other things, resisting a load applied to a side of an electrified vehicle using a reinforcement bracket secured to an outboard portion of a heel kick. The heel kick extends horizontally between rockers of the electrified vehicle. The heel kick and the reinforcement bracket are horizontally overlapped with each other.